The configure script of ncurses does not differentiate between build system includes and target system
includes. Thus, the host tools, which are first built and then run at compile time, use the wrong
include options when target and host system differ (they acutally use the target include settings
instead of the host settings which they are compiled for).
Fixing is to pull <wchar.h> in when _WINT_T is not yet declared while building the host tools.
